events: Add scancodes and keycodes for common application launcher keys

[Kontrabant]

Add scancodes and keycodes for common application launcher keys suggested by @muzikbike:

• The calculator key
• The email reader key
• The file browser key
• The local machine browser key (aka "My Computer")

@muzikbike, are there any other common launcher keys you've found since opening the original issue?

Closes #16047

• I confirm that I am the author of this code and release it to the SDL project under the zlib license. This contribution does not contain code from other sources, including code generated by a Large Language Model ("AI").

[slouken]

I pulled a whole bunch of these keys a while back. I'm not opposed to them returning, but you might want to look up that commit and just revert it, or see if there's something else that should come back.

[muzikbike]

I don't currently know of any. What I do want to do is buy a 2001 Microsoft Office Keyboard or similar, since it has buttons for launching spreadsheets/word processing applications and similar, which I think may be relevant. Microsoft really isn't great at documenting their scancode system, and I need to test if Linux maps them correctly.